There is conventionally known a display device for projecting projection images from a light source such as a projector onto a screen (projection surface) to display images.
A liquid crystal element is used as a screen of the display device of this kind in some cases. Generally, if a liquid layer device (liquid crystal display) is DC driven, its life is shortened. Therefore, an AC voltage driving operation for driving the display is carried out by applying AC voltage. Examples of AC applying methods are a frame inverting drive method, a line-line inverting drive method, a row-line inverting drive method, and a dot inverting drive method (see Patent Literature 1 as example of screen using AC driving type liquid crystal).
Patent Literature 2 proposes that using a transmission type liquid crystal display panel as a screen, transmittance of the screen is controlled to alternately switch between a transparent state and an opaque state, a picture of a viewer is taken by a camera placed behind the screen when the state is the transparent state, and an image is displayed as a display when the state is the opaque state.